The invention relates to compressed gas containers in general and, in particular, to an improved container for dispensing a product from an essentially pressureless, compressable product receptacle, which is enclosed by an elastically prestressed hollow cylinder forming a sealed clearance space containing a pressurized gas.
A container for spraying a liquid from a product receptacle enclosed by an elastically prestressed hollow cylinder made of elastomeric material is disclosed in DE-OS 3132906. As is evident from FIGS. 1-3 of this document, the hollow cylinder is expandable in one direction only, i.e. the longitudinal direction, and is elastically prestressed in this direction. The hollow cylinder is connected with a base that forms a can-like enclosure occupying the volume of the cylinder. The liquid to be sprayed is contained between the prestressed hollow cylinder and the can-like member. In the embodiments of FIGS. 9-10, an essentially pressureless, compressable product receptacle is provided which is pressurized by the con-like member. The pressure varies, as a function of the amount of liquid in the product receptacle, between a minimum pressure P.sub.min and a maximum pressure P.sub.max.
This type of device has numerous disadvantages. In addition to the high manufacture and assembly costs, the pressure drop that results during evacuation of the container is too large. This can cause a change in the consistency of the spray mist, which is intolerable. It is possible to reduce the pressure drop by increasing the initial stress applied while the product receptacle is completely empty, relative to the maximum pressure of the hollow cylinder. However, this results in other disadvantages which must be taken into account, such as a loss of delivery power and, thus, a lesser degree of admission of the product, i.e., a reduced amount of product relative to the size of the hollow cylinder.